# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: Apache-2.0

# Purpose:
# ec2-ruby-example-create-key-pair.rb demonstrates how to
# create a key pair in Amazon Elastic Compute Cloud (Amazon EC2) and
# saves the resulting RSA private key file locally in the calling
# user's home directory.

# snippet-start:[ec2.Ruby.createKeyPair]

require "aws-sdk-ec2"

# @param ec2_client [Aws::EC2::Client] An initialized EC2 client.
# @param key_pair_name [String] The name for the key pair and private
#   key file.
# @return [Boolean] true if the key pair and private key file were
#   created; otherwise, false.
# @example
#   exit 1 unless key_pair_created?(
#     Aws::EC2::Client.new(region: 'us-west-2'),
#     'my-key-pair'
#   )
def key_pair_created?(ec2_client, key_pair_name)
  key_pair = ec2_client.create_key_pair(key_name: key_pair_name)
  puts "Created key pair '#{key_pair.key_name}' with fingerprint " \
    "'#{key_pair.key_fingerprint}' and ID '#{key_pair.key_pair_id}'."
  filename = File.join(Dir.home, key_pair_name + ".pem")
  File.open(filename, "w") { |file| file.write(key_pair.key_material) }
  puts "Private key file saved locally as '#{filename}'."
  return true
rescue StandardError => e
  puts "Error creating key pair or saving private key file: #{e.message}"
  return false
end

# Example usage:
def run_me
  key_pair_name = ""
  region = ""
  # Print usage information and then stop.
  if ARGV[0] == "--help" || ARGV[0] == "-h"
    puts "Usage: ruby ec2-ruby-example-create-key-pair.rb " \
      "KEY_PAIR_NAME REGION"
    # Replace us-west-2 with the AWS Region you're using for Amazon EC2.
    puts "Example: ruby ec2-ruby-example-create-key-pair.rb " \
      "my-key-pair us-west-2"
    exit 1
  # If no values are specified at the command prompt, use these default values.
  elsif ARGV.count.zero?
    key_pair_name = "my-key-pair"
    # Replace us-west-2 with the AWS Region you're using for Amazon EC2.
    region = "us-west-2 "
  # Otherwise, use the values as specified at the command prompt.
  else
    key_pair_name = ARGV[0]
    region = ARGV[1]
  end

  ec2_client = Aws::EC2::Client.new(region: region)

  if key_pair_created?(ec2_client, key_pair_name)
    puts "Key pair created and private key file saved."
  else
    puts "Key pair not created or private key file not saved."
  end
end

run_me if $PROGRAM_NAME == __FILE__
# snippet-end:[ec2.Ruby.createKeyPair]
